Separation of tertiary olefins from gas mixtures



Patented Apr. 25, 1939 UNITED STATES PATENT OFFICE SEPARATION OF TERTIARY OLEFINS FROM GAS MIXTURES Georg Stern, Neckargemund, and Wilhelm Friedrichsen, many, assignors to I.

Ludwigshaten-on-the-Rhine, Ger- G. Farbenindustrie Aktiengesellschatt, Frankfort-on-the-Main, Ger- 7 many No Drawing. Application 5 Claims.

The present invention relates to the separation 01' tertiary oleflns from gas mixtures containing the same.

about 120 C. in the gaseous phase with a gasthe presence of a solid halide of magnesium or barium. In this way the tertiary oleflns are converted into the corresponding tertiary alkyl halides-which may be sepaverted gases or vapors.

As tertiary olcflns are intended those hydrocarbons which can be considered as being formed by splitting oif water from tertiary alcohols.

butylenes and butanes, or amylenes and pentanes, or hexylenes and hexanes. The separation of the tertiary alkyl halides may be effected for extional distillation, the alkyl recovered.

The tertiary alkyl halides may be used as such for a great variety of industrial purposes; they July 10, 1937, Serial In Germany July 18, 1936 may also be converted into tertiary alcohols or reconverted into tertiary oleflns. This may be effected directly by catalytic splitting 01! of hydrogen The reaction is usually carried out by leading the hydrocarbon mixture together with the hydrogen halide (preferably employed in an excess of about 10 per cent with reference to the tertiary butene-l and butene-2 are present in an excess, of ten times over the isobutylene. Other catatherefore only of slight industrial value.

The following examples will further illustrate the nature of this invention but the invention is not restricted to these examples. The parts are by weight.

Example 1 of hydrogen chloride and led in a uniform stream at 95 C. during the course of u 2 about 5 hours through a glass or porcelain tube over 1.5 liters of a porous barium chloride catalyst which has been prepared as follows:-

A mixture or equal parts of crystallized barium chloride and water is dried while heating by means of a powerful current of air to form a ve- The latter is broken up into pieces of about the size of peas and the water is completely expelled in a current of hydrogen chloride at from 150 to 200 C.

From the resulting reaction mixture, the tertiary butyl chloride is separated from the butene-Z by washing with aromatic hydrocarbons of high boiling point, as for example a pseudo cumol fraction. 115 grams (92 per cent of .the calculated yield) of tertiary butyl chloride are obtained from the pseudo-cumol solution by expelling it. It contains at the most up to 2 per cent of normal butyl chloride.

If the mixture or olefins and hyrdogen chloride be led at 95 C. under the same reaction conditions over a catalyst prepared in a corresponding manner from magnesium chloride, at tertiary butyl chloride of the same purity is obtained in a yield of '78 per cent.

If the mixture of olefins C. under the same conditions grams of hydrogen bromide per kilogram of the said mixture over a porous barium chloride catalyst prepared as described above, a very pure tertiary butyl bromide is obtained in a yield of '72 per cent. With barium bromide prepared in a similar manner tertiary butyl bromide of the same purity is obtained in a yield of 92 per cent.

Example 2 containing per cent or is passed at about 65 A pentene fraction together with 1600 r trimethylethylene in addition to a large amount of isopropylethylene. the said fraction having been obtained from an olefin mixture prepared from carbon monoxide and hydrogen under pressure, is mixed per each kilogram with about 550 grams of hydrogen chloride and led over a barium chloride catalyst at 95 C. in the manner described in Example 1. By distilling the washing liquid, 95 per cent of the trimethylethylene are recovered as the tertiary chloride.

What we claim is:

1. A process for the separation of tertiary olefins from gas mixtures containing the same which comprises treating such mixtures with a gaseous hydrogen halide at a temperature between about 50 and about'120 C. and in the presence of a solid halide of a metal selected from the group of barium and magnesium, the tertiary olefins thereby being converted into the corresponding tertiary alkyl halides, and then removing the latter item the remaining gas mixture.

2. In the process as claimed in claim 1 employing a solid halide in which the acid radicle corresponds to the halogen in the hydrogen halide.

3. A process as claimed in claim 1, in which the halides are chlorides.

4. A process as claimed in claim 1, in which the halides are bromides.

5. A process as claimed in claim 1, in which the hydrogen halide is employed in an excess of about 10 per cent with reference to the tertiary olefins. 

